1. Field of the Invention
The present invention generally relates to a system and method for lifting objects confined within a limited access space, and specifically to a system and method for lifting a heat exchange cooler motor in a natural gas processing facility.
2. Background of the Invention
In the course of processing natural gas in natural gas processing facilities, large heat exchanges or coolers are utilized. These coolers are comprised with structures that support large motors which drive fans. From time to time, these motors must be serviced and/or replaced. Because of the physical constraints of the cooler structure, removal of the motor is both time consuming and labor intensive.
The present disclosure provides a system and method which facilitates the servicing of cooler motors in gas processing facilities. The lifting system comprises a winch and pulley assembly, the pulleys being adapted to be mounted to a wall of the structure.
The lifting system comprises a removable winch and a dedicated pulley system. The winch is mounted to a winch plate which is adapted to be slideably and removably coupled to a receiver portion. This arrangement allows the winch to be removed when not in use. Or, the winch may easily be moved to another system. The receiver portion is coupled to a substructure supported by the cooler structure. A first pulley is mounted to an outside wall of the cooler structure. A second pulley is positioned at the end of a lifting arm which is coupled to an inside wall of the cooler structure. An opening is provided in the wall so that a winch cable may be threaded from the winch outside the structure, through the first pulley, through the wall opening to the interior of the structure, and over the second pulley, the end of the cable may then be secured to the motor. The motor can then be supported so that it may be disconnected from the cooler structure.
3. Description of the Prior Art
There have been a number of other patents and patent publication that teach lifting devices. For example, Falzer U.S. Pat. No. 1,461,650 teaches a lifting machine which may be used for raising equipment on a caisson or well and comprises a tripod having its apex approximately in line of the center or axis of the hole.
Howard U.S. Pat. No. 2,815,927 teaches a hoist which may be used to lift material along the longitudinal axis of an overhead track as well as materials that are beyond the end of the track. The Howard device comprises a rigid frame mounted on wheels for movement along an overhead track. The sheave housing may swing about a horizontal or vertical axis so as to allow the hoist to be used on objects outside the axis of the track and beyond its end.
Tucker U.S. Pat. No. 2,833,423 teaches a hoisting device which may be mounted to a vertical structure such as a telephone pole and which may be used to lift a heavy object such as a transformer.
Johnson U.S. Pat. No. 4,065,102 teaches a device which may be mounted to a structure such as a printing press frame to allow a hoist to lift rollers within the structure. The device is mound to the frame by means of an L-shaped. The device further comprises an extension arm and triangular shaped gussets or braces which allow the hoist to extend the line to lift objects within the frame.
Fowler U.S. Pat. No. 4,858,890 teaches a hoist and method for lifting objects inside a vessel having a platform on the exterior wall. The device is mounted to a frame on the outside of the vessel and comprises a cantilevered portion that extends through the wall of the vessel through an inspection port.
Williams U.S. Pat. No. 5,056,673 teaches a hoist for lifting electrical equipment such as transformers. The device is removably mounted to a pole.
Simon U.S. Pat. No. 5,482,169 teaches a lifting device which may be used in an enclosure which is inaccessible to operators such as tight cells or chambers used in the nuclear field for confining radioactive materials. The device comprises a main arm which may be inserted through hole within a sleeve to allow the operator to move objects found within the enclosure while the operator is outside the enclosure. The apparatus is supported by the shield 1 and wall frame of the shield.
Baker U.S. Pat. No. 5,765,809 teaches a device for lifting items. The device may be mounted on a particular piece of equipment. The device comprises a receiver which may be welded to the base of the machinery. The receiver allows the vertical piece to rotate. The vertical piece is attached to a generally horizontal hollow pipe which may comprise two separate hollow pipes.
Walker U.S. Pat. No. 6,041,949 teaches an overhead lifting device for use in lifting an electrical switching apparatus. The device comprises a moveable support frame which moves along first and second rail members mounted to the electrical cabinet.
Zingeman U.S. Pat. No. 6,478,172 teaches a portable lifting device which may be used to lift heavy objects through a window or opening in a structure. The apparatus includes a trolley installed in a girder. The frame is connected to the telescopic posts which support the assembly within the structure. The girder allows the trolley to move material from outside the building to inside the building.
Kuipers U.S. Pat. No. 7,189,047 teaches an apparatus for moving a battery. The apparatus is mounted to a shelf which contains batteries.
Bailey U.S. Pat. No. 7,407,039 teaches a portable lifting device which may be mounted to the outside of the structure.
Lichinchi U.S. Pat. No. 7,604,134 teaches a portable knock down trolley hoist which may be used to lift heavy objects. The hoist comprises an overhead trolley support member having a top portion and bottom portion in a trolley mounted on roller bearings that allow the trolley to be moved from a position along the rail.
Gaines Patent Publication US2009/0095944 teaches a lifting apparatus which may be mounted to a permanently affixed ladder (see Gaines FIG. 5). The device comprises a hoist mounted on a mast which extends through a hatch opening in the roof of a building.
Varildengen Patent Publication US2004/0238472 teaches a hoist which may be mounted to a window opening, shell of a building, etc. and comprises a central post portion (see Varildengen FIG. 1) to which the hoist may be mounted.
Tien Patent Publication US2005/0236352 teaches a portable crane that can be set up on a rooftop.
Choate Patent Publication US2006/0163186 teaches a hoisting device which may be used in securing a person working in elevation. The device may be mounted on a base comprising leveling screws and casters.
As may be noted, none of the foregoing references teach the lifting device and method of the present invention. Specifically, none of the references teach a device comprising an outer portion mounted to an outer wall of a structure, an inner portion mounted to an inner wall of a structure which allows a winch, mounted on the outside of the structure, to operate outside the building and lift objects within the structure.